Do push notifications work well in Firebase?

Question

Android

Hello! You need to make push notifications in the application, the peculiarity is that you need fast delivery, because in a few minutes they will no longer be relevant.
I read a lot of negativity about Google Cloud Messaging. Now, as I understand it, they have transferred everything to Firebase, so the question is whether it works well now.
And if not, what are the alternatives? I understand that keeping a connection with the server or periodically polling the server is not an option - it drains the battery. What other technologies are there?
Thanks in advance!

Answer 1

GCM / FCM are native for android, their server eats up battery when used inaccurately.
FCM works about the same as GCM in terms of speed
On a device that does not restrict background connections, there are no delays in delivery, a maximum of 3-4 seconds with poor Internet